diff --git a/layouts/partials/opengraph.html b/layouts/partials/opengraph.html
index baf8cbb804..20ff74e361 100644
--- a/layouts/partials/opengraph.html
+++ b/layouts/partials/opengraph.html
@@ -20,7 +20,7 @@
 {{- end }}
 
 {{- with site.Language.LanguageCode }}
-    <meta property="og:locale" content="{{ . }}">
+    <meta property="og:locale" content="{{ replace . `-` `_` }}">
 {{- end }}
 
 {{- if .IsPage }}